A search engine is a type of program that may be hosted and executed by a server. A server may execute a search engine to enable users to search for documents in a networked computer system based on search queries that are provided by the users. For instance, the server may match search terms (e.g., keywords) that are included in a user's search query to metadata associated with documents that are stored in (or otherwise accessible to) the networked computer system. Documents that are retrieved in response to the search query are provided to the user as respective search results. The documents are often ranked based on how closely their metadata matches the search terms. For example, the documents may be listed in an order that corresponds to the rankings of the respective documents. The document having the highest ranking is usually listed first in the search results.
Search engines traditionally are configured to restrict a number of search results that are allowed to appear from each domain or host to no greater than a maximum number in order to maintain diversity among the search results. Some search queries may indicate a relatively strong intent to obtain search results from particular domains or hosts. For instance, the search query “music videos youtube” may indicate a relatively strong intent to obtain search results corresponding to music videos from YouTube®. However, even when a search query indicates a relatively strong intent with regard to a domain or host, conventional search engines continue to limit the number of search results that are provided from that domain or host to be no greater than the maximum number.
Conventional search engines may be capable of recognizing operators in a search query that are intended to increase relevance of search results that are provided in response to the search query. For example, a “site:” operator may be included in a search query to indicate that corresponding search results are to be retrieved from only a specified web site. However, the use of such operators by a user requires the user to have knowledge of the operators and to configure a search query to incorporate the operators, which may be inconvenient.